/* Copyright (c) 2001-2008, The HSQL Development Group
 * All rights reserved.
 *
 * Redistribution and use _in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * Redistributions _in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer _in the documentation
 * and/or other materials provided with the distribution.
 *
 * Neither the name of the HSQL Development Group nor the names of its
 * contributors may be used to endorse or promote products derived from this
 * software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL HSQL DEVELOPMENT GROUP, HSQLDB.ORG,
 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */


using System;

namespace EffiProzDB
{

    /*
    * This class introduces iterator functionality to Result.
    *
    * @author fredt@users
    * @version 1.7.2
    * @since 1.7.2
    */
    public class ResultBase
    {

        public Record rRoot;
        protected Record rTail;
        protected int iSize;

        public ResultBase() { }

        public ResultIterator iterator()
        {
            return new ResultIterator(this);
        }

        public class ResultIterator
        {
            private ResultBase _o;

            public ResultIterator(ResultBase _o)
            {
                this._o = _o;
                current = _o.rRoot;
            }

            bool removed;
            int counter;
            Record current ;
            Record last;

            public bool hasNext()
            {
                return counter < _o.iSize;
            }

            public bool next()
            {

                if (hasNext())
                {
                    removed = false;

                    if (counter != 0)
                    {
                        last = current;
                        current = current.next;
                    }

                    counter++;

                    return true;
                }
                else
                {
                    return false;
                }
            }

            public bool previous()
            {
                return false;
            }

            public bool absolute(int rows)
            {
                return false;
            }

            public bool relative(int rows)
            {
                return false;
            }

            public bool beforeFirst()
            {
                return false;
            }

            public bool afterLast()
            {
                return false;
            }

            public bool isBeforeFirst()
            {
                return false;
            }

            public bool isAfterLast()
            {
                return false;
            }

            public void remove()
            {

                if (counter <= _o.iSize && counter != 0 && !removed)
                {
                    removed = true;

                    if (current == _o.rTail)
                    {
                        _o.rTail = last;
                    }

                    if (current == _o.rRoot)
                    {
                        current = _o.rRoot = _o.rRoot.next;
                    }
                    else
                    {
                        current = last;
                        last = null;
                        current.next = current.next.next;
                    }

                    _o.iSize--;
                    counter--;

                    return;
                }
            }
        }
    }
}
